The invention concerns medical equipment for dental use.
Before operating on a tooth to remove decay or for other purposes it is known that the vascular and nerve tissue inside the canal in the root of the tooth concerned has to be removed.
This is done by introducing into said canal an instrument which by lateral and rotary movements can bring to the surface the material inside it. There may be one or more canals according to the type of tooth. The operation may involve some considerable difficulty because of curves in canals and their divisions.
The instrument used for the purpose does not always achieve the desired results because of the above-mentioned anatomical characteristics. This operation is long and laborious.
It also requires repeated X-ray checks to see that the work is proceeding correctly. To ensure that the canal has been devitalized it is essential not only to clean it out but also to avoid penetrating beyond the lower end of each canal.
A certain distance, about mm 1.5, must be maintained from the apical foramen to avoid infection and bacterial complications generally. Bearing in mind that to devitalize the canal root is a dental treatment that requires great precision and careful attention, dealing correctly with the problems that arise using present methods must clearly depend on the dentist""s ability.
The present invention eliminates the above drawbacks almost entirely both as regards the patient and the operator as will be explained below. Subject of the invention is a process to devitalize the canal root of a tooth in which the vascular nervous material receives a fractionally long high frequency electric pulse, power values, time and frequency, being adjusted to suit the type of tooth.
To carry out this procedure an electrode in the form of a needle is inserted into the canal in the root; the electrode is of a length that allows it to penetrate until it reaches the right distance from the apical foramen and is connected to a pulse-generating apparatus.
Emission of high frequency pulses can be assisted by electrically connecting the electronic circuit that generates them to some other part of the patient""s body, the hand for example, by a so-called neutral handle-type metal object, or by some other suitable tool.
The effect of this high frequency pulse that acts only along the whole surface of the needle-type electrode, is to disintegrate the vascular nerve matter and simultaneously coagulate the part of the vascular bundle that is not destroyed, as well as to sterilize the root canal.
In order to insert the needle-type electrode into the root canal, anaesthetic is applied to the area of the tooth concerned which is then opened up till entry into the root canal is visible.
The high frequency electric pulse is preferably provided by an apparatus that comprises an electronic circuit able to estimate the correct distance from the apical foramen to which the needle must penetrate and to give an acoustic and visual warning as soon as that position is reached. In this way the operator can have suitable electric current generated for destroying the nerve bundle in the root canal when the needle has reached the above position.
Closure of the electric circuit is preferably pedal-operated.
Values of electric current suitable for destroying the nerve bundle in the root are automatically regulated by the electronic apparatus according to which of the four buttons is pressed, these being respectively for the four types of teeth: incisor, canine, premolar and molar
Value of the electric current can be increased by pressing a button for this purpose placed on the apparatus.
The needle-type electrode, preferably of stainless steel, that transmits the high-frequency pulse, can be of different lengths, average mm 30, and may be of a tapering structure with a base diameter of about mm 0.25 and a tip diameter of about mm 0.1.
In a preferred execution the needle has a haft, about mm 1 in diameter, comprising a rear section about mm 15 long and a front section about mm 5 long set at an angle of about 110xc2x0 in relation to the rear section.
The apparatus that actuates the described process comprises a cable for electric feed, a cable for pedal control of the devitalization pulse, a socket for a cable connecting it to a so-called active handle of insulating material with a metal core, and can comprise a socket for the cable connecting it to the so-called neutral handle.
At the front end of said active handle is a head into which the needle can be introduced and fixed.
The cable connected to the so-called neutral handle can include insertion of a branch cable to carry a kind of pincer which is preferably applied to the lip of the patient during the measuring operation.
The apparatus here concerned may be equipped with the following main electronic circuits: input filters, feeder, RF pulse generator or pulser, for setting output power, a power visualizer for setting Burst time, for the change-over from manual to automatic functioning or vice versa, for protection against an increase in the output power setting, for safety to prevent involuntary repetition of the devitalization movement before a set time, for example 10 seconds, has passed, for an acoustic two-tone warning when, during the measuring operation, the needle has penetrated to the correct distance from the apical foramen and for a single-tone sound to indicate that the devitalizing electric pulse has been given and that the operation has therefore been completed.
The process offers evident advantages.
Present mechanical methods involve a risk of bacteria remaining in the canal of the root that may lead to pathological conditions of the tooth or of its adjacent structure producing haemorrhage or infection.
The method described makes it possible to devitalize the root canal quickly and painlessly using very little anaesthetic which is therefore less toxic for the patient.
After the operation the root canal is completely sterilized both in its main part and in its lateral branches.
Any haemorrhage or infections are entirely avoided.
The risk is also avoided of penetrating beyond the apical formen, a risk always present with the manual instruments in use, and one that can lead to considerable complications.
To sum up these advantages, with a small low-cost easily operated apparatus, for the first time in the field of dentistry apical measurement and electronic devitalization can be done limiting the operation exclusively to disintegration of the vascular nerve bundle.
In conclusion, this method enables both dentists and patients to undertake dental treatment in an entirely new way which offers important advantages, not only in time and cost but also in patient comfort, maximum reliability and elimination of errors.